speeding up 'dendToTree' function

[tomasreigl]

Hello,

thank you for doing a really nice work on the d3heatmap package!
I'm visualizing quite a big dataset and when I was profiling my shiny app, quite a lot of time is taken by dendToTree function in dendrogram.R script. Do you have any idea how to speed it up?
The second most time consuming function is dendextend::color_branches, but I don't want to touch internal dendextend functions...

Thank you for any tips/ideas!